privileges problem

while configuring dynamic virtual hosting (with mod_vhost_alias) on a new
server i ran into this problem
i create a new group named g(username) for each new virtual web, I set all
user files to chmod 640 to avoid them to be read by another user
my apache server runs as www-data so i need to add user www-data to each
virtual web group to be able to serve its documents
this all works fine but
when I create a new virtual web, that means a new group, user and home
directory and try to access its documents via http I get this error in the
apache error.log
Permission denied: /home/html/inko.sk/public_html/.htaccess pcfg_openfile:
unable to check htaccess file, ensure it is readable
everything works well after restarting the apache server, it looks like the
running apache server doesn't know that the user it runs as (www-data)
became a member of the new group created for the new virtual web
is there a way to somehow refresh this info for the running process without
restarting it?
do you have another suggestion?
If I have to restart apache every time I add a new server then I am on the
beginning and usibng mod_vhost_alias didn't help at all.
thanks
Martin Dragun